Catalytic treatment of hydrocarbons



May'18, 1943 wl L BENEDIICT CATALYTIC TREATMENTOF HYDROCARBONSV Filed May le, m41

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Patented May 18, 19h43 A l 2,319,199 c v TMENT or HYDRO-- ARBON S 1. Wayne BenedictrChlcago, Ill., assignor to Uni# .versal 0il-Products Company, Chicago, Ill.,a

' c corporation o! Delaware Application May 16,1941',s'eria1N0. 393,704

' `comms. (ci. 19e- 54) .friventionrelates to the treatment of hy-f drocarbon' oils inthe presence of catalysts rto n cover hydrogen chloride? and, the recovered hy-l. .l

produce high antlknock gasoline. More specifl-A cally it is directed tothe more effective utilization of, catalystspf'thealuminum chloride V4type in cracking and *reformingy reactions and to more suitable Contact conditions' of the catalyst and oil undergoing. conversion treatment.`

It isgenerally known that a relatively saturated gasolineof high octane number having goodlead susceptibility is 'obtained inthe aluminum ,chloride I type of conversion of hydrocarbon oils. .Itisalso known that theV hydrocarbon gases from the process contain relatively large amounts "of lsobutane whichA is particularly valuable'. in the' manufacture; of.v alkylated K hydrocarbons useful in aviation fuels'.f v1t isl yamong the objects of thefpresent" invention to obtain vincreasedlyields oflthefhigh antiknock saturated gasoline, {is'obutane and .other valuable products j in the.aluminuml chloride cracking process. Y In one s'pecic embodiment, the present in-A Veriton'- comprisesA c'ommingling the hydrocarbon oilbhar'ging stock with a` relatively clean, partia'lly ea'ctedA oil Afrom 'the process and heating' thegconmingd on .to catalytic cracking conditions, 'directing the heated commingled oilinto a. reaction chamber and crackingcatalytically while essentially in the liquid phase, adding aluminum'chloride catalyst andhydrogen chloride theretopwithdrawing partiallyl reacted'oil ycon 'taining laluminum chloride sludge to a settling chamber to separate relatively clean, partially reactedoil :from an oil andl catalyst sludgemix-v ture, returning the relatively clean, partiallyfre-V acted oil ',to. further treatmentrcommingled with" hydrocarbon charging oil ras hereinabove 'setvv forth, withdrawing a portion of the separated loil and aluminum chloride sludge mixturefromthe process, mixing the remaining' portion With'fresh catalyst and adding to theoil as hereinabove set forth,premoving vaporousreaction .products from the reaction chamber and 4fiactionating*the va;

porsf'to separate gasoline boiling rangehydrfo-` carbons and cracked -gases fromhighcry boiling hydrocarbons, cooling and sepa-rating the gaso- 1 tion vessel. The oil is Withdrawn from thereaction zone and is cooled to -a temperature 'at which .substantially no reaction takes ,place` and where the oil -andfcatalys't sludge can be readily segregated. The sludge is vcatalytic in nature and in order` to obtain the maximum utility drogenv 'chloride is returned to the process.

According to the process of the present inven` tion, a hydrocarbon oil suchas a gas oil or kerosene fraction, or a gasoline boiling range yfraction having low antiknock value, is processed in. the presence of a metal halide cracking catalyst under cracking conditions: adapted to prevent lor minimize the formation of coken in the reaction chamber by maintaining a circulation of. theoil.

undergoing conversion treatment. .The oil and catalyst mixture Afrom* Yconversion ,treatment ris removed to a-separating and settlingchamber where relatively clean oil is essentiallyA separated from. oil containing aluminum' chloride complex. The relatively clean -oil is Withdrawn andafter mixing with fresh charging oil is heated to a catalytic conversion temperature and vdirected to the reaction chamber. catalyst complex, particularly the heavier' sludge portion-thereof, is removed from` the process kwhile partially reacted hydrocarbon oil containingl in suspension partially spent catalystis mixed with fresh catalyst and is then'directe'd c v to thereaction chamber vpreferably without pre`` heating. A static condition in the reaction chamber is thus avoided in which a'he'avy coke'- forming sludge adheres to the sides of the reactherefrom should be'recirculated to the process.

According tothe presentl linvention this can be done vwithout the necessity for heating it by passing it through heated coils or in contaetwith otherfexternally' heated surfaces whereby the lineboiling range hydrocarbons from gases ,con`

taining isobutane and' hydrogen chloride.

l In'a further embodiment, .theV higher-.boiling hydrocarbons separated Lfrom the gasoline boiling- `range hydrocarbons'areheated and reactedl in mixture with the oil undergoing said catalytic cracking treatment andthe gases from the process are subjected to separation treatment to retendency for the4 sludge to deposit coke-like ma,-

terials is enhanced. If aluminum chloride sludge I is heated in the absence of charging stock it is reduced to a 4material of heavier and more viscous? character.

If vit is heatedY While mixedwith charging stockwithwhich itis not completely miscible there is a tendency for the heavyfsludge to deposit unl-the heated surfaces and to be re#y duced to solid or semi-'solid material. I This may result in the ultimate coking up of the heating surfaces, thereby reducing the heat transfer to the reactants and` moreover resulting in loss of valuable .catalytic material. c

.The present invention permits recirculation of sludge while at the same time carryingout the' process in an efcient manner at theI desired 'I'he oil containing the temperature.' The temperature is attained by heating the catalyst-free oil to a temperature sufficiently above that desired in the reactor so that the temperature in the reaction zone is brought to the desired pointwhen the oil and catalyst are mixed therein. The catalyst is in the form of a uid sludge but during the time in which it is being pumped .outside of the retional side elevation one specic form of apparatus which may be used to accomplish the objects of the invention. It is not drawn to any exact or relative scale and serves only as an illustration of the process constituting the in- 1 vention.

action zone it is at a temperature wherein the I reaction velocity is so slight that the undesir- Referring to the drawing, a clean hydrocarbon oil such as a. light topped crude oil, or preferably a hydrocarbon oil fraction such as a gas oil, arkeros'ene distillate or `a fraction boiling within the gasoline boiling range having a low antiknock value, is charged to the process through line .I regulated by valve 2 leading to pump 3 which pumps this oil through line 4' conhydrogen chloride is added-preferably in anhydrous form, and Amay be added either tothe oil 4undergoing cracking after heat treatment or may be added to the sludge being recirculated or it maybe added directly to the reaction zone. The quantity of hydrogen chlorideis comparatively small and there is little or no consumption in the process. As a consequence it may be recov red from the final reaction products and rec rculated.

The reactions involved in aluminum chloride cracking are generally known. -There is a severing of carbon-to-carb'on bonds, particularly with higher boiling hydrocarbons to form lower boiling hydrocarbons. There'is also a decyclization of naphthenes and an isomerization of straight chain hydrocarbons to form more highly branched compounds therefrom; In the present process there appears to be less'of the polymerization reactions in which there is formation ofl lower layer with the metal halide catalysts.

This may be because the catalytic sludge taining` valve 5 into line 6 and mixing with partially reacted voil which mixture then flows to the heating-element v'I located in furnace 8. The' oil is heated to a catalytic reaction temperature and directed through line 9-regulated by valve III to an intermediate point in the height of the reaction chamber II where it is mixed with the catalyst and is reacted as subsequently described. Hydrogen chloride is preferably added to the oil to aid the aluminum chloride cracking and may be introduced through kline 56 regulated by valve 51 -into the heated oil flowing through line 9 into the reaction chamber. Partially reacted oil containing catalyst complex formed lis never heated above the optimum temperature for conducting the reaction and it is never brought into contact with an externally heated surface. y

Desulfurization reactions may occur, resulting in reduction or elimination of sulfur from the products.

The operating conditions may be varied over a wide range depending upon the charging stocks, the amount of catalyst, the metal halide chosen, and other features such as the products desired and their quality. For example, the temperature maybe within a range of about 400 to about '100.c F. Pressures may vary widely from substantially atmospheric toy 500 pounds or more per square inch. The quantity of catalyst present in the system at `any one time may vary considerably from less than one per cent to approximately ten per cent of the oil processed. In certain instances, when employing aluminum chloride even larger quantities may be present in the apparatus but the ultimate consumption of aluminum chloride is usually less than one or` two per cent by weight of the oil converted. The

amount of hydrogen chloride circulated is normally less than ve per cent by weight vof aluminum chloride employed.

The features of the invention will become more apparent inl the description of the flow and operating conditions described in connec-` tionwith the attached drawing. The drawing illustrates vvdiagramrnatically and in convenand catalyst sludge is rremoved from the lower part of reaction chamber Ii through line I2 and may under some conditions be removed through valve I3 as will be subsequently described. In most operations, however, the mixture of oil and catalyst is removed from` line I2 through line I4 containing valve I5 and cooler I5 and is directed` to the separating and settling chamber I6 forsepa'ration of a relatively clean hydrocarbon oil fraction ,from oil containing thecatalyst complex and catalyst sludge. In the case of thel cracking of heavier oils, such as gas oil in the presence of aluminum chloride catalyst, it may be desirable to permit the-settling of a relativelyheavy sludge in the bottom ofthe reaction chamber II which is thenremoved `through line I2 and valve I3 while thel circulation of Voil through the chamber is maintained by removing oil at a higher level as illustrated by withdrawing'the oilv through line I1 regulated'by valve I8' and admitting this oil to line I4 through which it flows to chamber I5 for separation as has been described. Relatively clean oil, more or less free from catalyst, is removed from the top of separating chamber I6 through line I9 containing valve 20 and flows to pump 2I which pumps this oil through line i containing valve 22 where it mixes with charging oil and is then admitted to the heating element for treatmentas has been hereinabove set forth.

Hydrocarbon oil settling out in chamber I6 and containing aluminum chloride complex and sludge, is removed from the lower part thereof through line 23 and may be withdrawn in part from the process through valve 24.101' separation and recovery treatment to recover oll and aluminum chloride therefrom. The major portion of the settled oil and catalyst material however flows from line 23 into line 25 containing valve 26. Aluminum halide catalysts may be added aaraiee o 3 sumed catalyst withdrawn at a higher level as illustrated by withdrawing this oil and catalyst suspension through line 2E regulated by valve 29.

leading into line 25. The catalyst mixture is pumped by pump 32 through line 33 containing valve 34 to the distributing means in the reaction zone illustrated as 35 in the upper portion of reaction chamber i I. This distributing means may, for example, consist of a perforated ring or a conical baille plate.

Gasoline containing vapors and gases are removed from the upper part of the reaction chamber il through line 38 regulated by valve 31 and leading to fractionator 38 where gasoline boiling range hydrocarbons and gases are separated from higher boiling hydrocarbons. The higher boiling hydrocarbons are removed from the lower part of fractionator 38 through line 39 regulated by valve 40 andl may then be removed from the process or subjected to further catalytic conversion treatment by means not shown, as for example by mixing with the oil flowing through line i for heating and cracking treatment. Gasoline containing vapors and gases are removed from the fractionator 38 through line 4l containing valve 42 leading to the condenser 43 where these products are cooled and condensed. The cooled and condensed products are then directed through line 44fcontaining valve C5 into the re1 ceiver 46 where the gasoline boiling range hydrocarbons are separated from gaseous products. vA portion of the gasoline boiling range hydrocarbons collected in the lower portion of receiver 46 are removed through line 4l containing valve 48 and leading to pump which pumps this oil through line 50 containing valve 5l to the upper part of the fractionator 38 for the purpose of assisting in the regulation of the end boiling temperature of the gasoline product. Gasoline boiling range hydrocarbons are withdrawn from receiver 46 through line 52 regulated by valve 53 and gaseous products are removed through line 54 regulated by valve 55. The gases thus removed contain isobutane. other valuable hydrocarbons and also hydrogen chloride which is preferably recovered by conventional means not shown and returned to the process together with the fresh hydrogen chloride admitted thereto through line 56 regulated by valve 5l.

Tile following specific example is given to illustrate a specific application of the process of the invention. 'Ihe invention should not be considered as limited to this example or to the particuiar catalyst used since these are given to illustrate the utility of the invention.

A 36 A. P. I. Pennsylvania gas oi1 is heated to a temperature of approximately 650 F. at a pressure of approximately 200 pounds per square inch and is then directed into a reaction chamber where it is mixed with approximately 5 per cent by weight of anhydrous aluminum chloride and one-fourth of one per cent of hydrogen chloride. Catalytic crackingk occurs in the reaction chamber and oil and partly used catalyst is withdrawn from the lower part of the reaction chamber. Partially cracked oil approximately equal in amount to the gasoil charged to the process is separated from oil having concentrated therein the partly used catalyst and catalyst sludge, and is returned to the process togetherwith the gas oil charge. The oil containing the partly used catalyst and sludge is settled to separate the heavy catalyst sludge in the oil which is removed from the process while the oil and partly used catalyst is mixed with fresh catalyst and is then returnedto the process for contacting with the oil to be cracked. Gasoline containing vapors from the chamber are fractionated to separate the desired gasoline product. The 400 F. endpoint gasoline has an octane number of 75, is

Y highly saturated and corresponds to a yield of minum chloride.

approximately per cent based on the gas oil charged to the process.

I claim as my invention:

1. A conversion process which comprises cracking hydrocarbon oil while in admixture with a metal halide catalyst in a vertical `reaction zone, removing admixed oil and catalyst from the lower portion of the reaction zone and separating from the mixture a relatively clean oil and a liquid containing suspended catalyst, adding charging oil for the process to said relatively clean oil and heating the commingled oils to cracking temperature, introducing the heated oils to the reaction zone at an intermediate point in the height thereof, adding fresh metal halide catalyst to said liquid containing suspended catalyst, introducing the resultant mixture to the upper portion of the reaction zone, above said intermediate point, removing vapors from the upper portion of the reaction zone and subjecting the same to fractionation and condensation.I

2. The process as defined in claim 1 further characterized in that the catalyst comprises alu- 3. The process as defined in claim l further characterized in that a hydrogen halide is introduced to the reaction zone together with said heated oils.

4. The process as defined in claim 1 further characterized in that the catalyst comprises aluminum chloride and in that hydrogen chloride is introduced to the reaction zonel together with said heated oils.

' WAYNE L. BENEDICT. 

